Wordpress Multisite Install: Fatal Error with PHP 7

[mack-linebaugh]

I had this plugin up and working on a single install of Wordpress 5.1 and PHP 7.2. I decided to switch it a multisite install. Afterward, I couldn't activate the plugin. I deleted it, reinstalled it, and kept getting the same error:

Fatal error: Uncaught ArgumentCountError: Too few arguments to function wpdb::prepare(), 1 passed in /npr-story-api/ds-npr-api.php on line 74 and exactly 2 expected in /wp-includes/wp-db.php:1295 Stack trace: #0 /npr-story-api/ds-npr-api.php(74): wpdb->prepare('SELECT blog_id ...') #1 [internal function]: nprstory_activation('') #2 /wp-includes/class-wp-hook.php(286): call_user_func_array('nprstory_activa...', Array) #3 /wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array) #4 /wp-includes/plugin.php(465): WP_Hook->do_action(Array) #5 /nas/content/live/nashpubraddev/wp-admin/plugins.php(177): do_action('activate_npr-st...') #6 {main} thrown in /wp-includes/wp-db.php on line 1295

So the error originates in this function (line 74, referenced in the error message, is in bold):

function nprstory_activation() {
global $wpdb;
if ( function_exists( 'is_multisite' ) && is_multisite() ) {
// check if it is a network activation - if so, run the activation function for each blog id
$old_blog = $wpdb->blogid;
// Get all blog ids
$blogids = $wpdb->get_col( $wpdb->prepare( "SELECT blog_id FROM $wpdb->blogs" ) );
foreach ( $blogids as $blog_id ) {
switch_to_blog( $blog_id );
nprstory_activate();
}
switch_to_blog( $old_blog );
} else {
nprstory_activate();
}
}

From Wordpress documentation:

With the upcoming PHP 7.1, former warnings when passing too few arguments to a function got raised to an ArgumentCountError exception with the following format: Fatal error: Uncaught ArgumentCountError: Too few arguments to function foobar()

Anyone know of a fix for this? One that doesn't involve editing wp-db.php, class-wp-hook.php, and plugin.php?

[jwcounts]

It looks like the main issue is with the usage of $wpdb->prepare, since it expects 2 arguments and only one is provided.

https://developer.wordpress.org/reference/classes/wpdb/prepare/

It's preforming a sprintf() find-and-replace on the query, and it's expecting something like this:

$blogids = $wpdb->get_col( $wpdb->prepare( "SELECT blog_id FROM %s", $wpdb->blogs ) );

[mack-linebaugh]

I'm pasting this solution I generously received from @jwcounts on Slack, which solved the issue for me:

The $wpdb->prepare() function in Wordpress, which is referenced in the nprstory_activation() function, needs 2 arguments to work correctly: a query with placeholders, and the data to replace those placeholders.

Example:
$wpdb->prepare( 'SELECT blog_id from %s', $wpdb->blog );
The %s is a placeholder for a string, and the $wpdb->blog is the string that will replace it. The prepare() function performs this replacement in order to help organize and sanitize the query

So, line 74 in the ds-npr-api.php should look like this:
$blogids = $wpdb->get_col( $wpdb->prepare( "SELECT blog_id FROM %s", $wpdb->blogs ) );